Characteristics of Dutch and Swiss primary care COPD patients - baseline data of the ICE COLD ERIC study

Yoga and music intervention reduces inattention, hyperactivity/impulsivity, and oppositional defiant disorder in children's consumer with comorbid ADHD and ODD

Introduction

To analyze the impact of yoga and music intervention on child consumers, we selected 60 eligible child consumers from yoga and music companies.

Methods

This preliminary study used a randomized controlled design to investigate whether a 16-week combined yoga and music intervention improves attention, hyperactivity/impulsivity, and oppositional defiant disorder (ODD) in 60 children with attention-deficit/hyperactivity disorder (ADHD) comorbid with ODD aged 4-6 years. It also preliminarily identified which intervention is best for these children among three types: combined yoga and music, yoga-only, and musiconly interventions. We used both the parent- and teacher-rated MTA SNAP-IV ADHD Rating Scale for data collection.

Results

We found that the combined yoga and music intervention had a positive effect on inattention, hyperactivity/impulsivity, and ODD in children with comorbid ADHD and ODD. The combined yoga and music intervention was the most effective in reducing inattention (in repeated measures ANOVA effect size, 0.9; followed by the yoga- and the music-only interventions, respectively), hyperactivity/impulsivity (effect size, 0.92), and ODD behaviors (effect size, 0.93) in children with comorbid ADHD and ODD. Thus, the combined yoga and music intervention was the most effective and had a more comprehensive effect on children with combined ADHD and ODD compared with the two other interventions (i.e., yoga- and music-only interventions).

Discussion

Our findings provide preliminary evidence for the use of combined yoga and music interventions on a daily basis as a safe and effective adjunctive treatment for children with comorbid ADHD and ODD. The children in the article refer to child consumers of yoga and music companies.

Personalising add-on treatment with inhaled corticosteroids in patients with chronic obstructive pulmonary disease: a benefit-harm modelling study

BACKGROUND

Since the benefit-harm balance of adding inhaled corticosteroids to long-acting β₂-agonists (LABA) and long-acting muscarinic antagonists (LAMA) for patients with chronic obstructive pulmonary disease is unclear, we evaluated this addition for a range of patient profiles.

METHODS

Analyses considered the effects of low-to-moderate doses of inhaled corticosteroids, LABA, and LAMA compared with LABA and LAMA alone, outcome incidences, and preference weights assigned to averted moderate-to-severe exacerbations (benefit) and severe pneumonia, candidiasis, and dysphonia (harm). Using exponential models, we estimated the preference weight-adjusted 2-year net clinical benefit (ie, benefits outweighing harms) indices. Exacerbation risk thresholds for triggering inhaled corticosteroids, LABA, and LAMA were established when the probability of a 2-year net clinical benefit reached 60%. We estimated the proportion of patients benefiting from added inhaled corticosteroids using an externally validated prediction model for acute exacerbations in primary care.

FINDINGS

Adding low-to-moderate dose inhaled corticosteroids to LABA and LAMA provided a net clinical benefit in patients with a 2-year baseline exacerbation risk of 54-83%. Low-dose inhaled corticosteroids showed a net clinical benefit if the baseline risk was 40-91%, but not at higher doses. The benefit was modified by blood eosinophil count (BEC) and age. Although no net benefit was associated with a BEC of less than 150 cells per μL, patients with a BEC of 150 cells per μL or more had a net benefit from low-dose inhaled corticosteroids with a 2-year exacerbation risk of 32-95% in those aged 40-79 years and 41-93% in those older than 80 years. A moderate dose of inhaled corticosteroids showed a net benefit in patients younger than 80 years with a BEC of 150 cells per μL or more at 52-86% 2-year exacerbation risk. Depending on the subgroups, the proportion of patients with a net benefit from added inhaled corticosteroids ranged from 0 to 68%.

INTERPRETATION

The net clinical benefit of adding different inhaled corticosteroid doses to LABA and LAMA varies greatly with exacerbation risk, BEC, and age. Personalised treatment decisions based on these factors and predicted exacerbation risks might reduce overtreatment and undertreatment with inhaled corticosteroids.

FUNDING

None.

Multimorbidity at sea level and high-altitude urban and rural settings: The CRONICAS Cohort Study

Objective:

To characterize the prevalence and clustering of multimorbidity in four diverse geographical settings in Peru.

Methods:

Multimorbidity, defined as having ≥2 chronic conditions, was studied in adults aged ≥35 years in four diverse settings in Peru: Lima, Tumbes, and urban and rural Puno. Six of these conditions (alcohol disorder, asthma, chronic obstructive pulmonary disease, depression, diabetes, and hypertension) were cataloged as objectively ascertained chronic conditions and paired in dyads to explore clusters of multimorbidity.

Results:

We analyzed data from 2890 adults, mean age 55.2 years, 49% males. Overall, 19.1% of participants had multimorbidity, ranging from 14.7% in semi-urban Tumbes to 22.8% in Lima. The dyads with the highest coexistence (approximately 20%) were observed in hypertension and diabetes in Tumbes, whereas the dyads with lowest coexistence (approximately 1%) were those involving asthma in all study sites. In terms of clusters, Tumbes showed a predominance of hypertension and diabetes, urban and rural Puno a predominance of depression and alcohol disorders, and Lima a higher degree of coexistence of all of the six conditions than in the other clusters.

Conclusion:

Multimorbidity is common and the pattern of clusters is highly heterogeneous. The conditions to prioritize will vary in each setting.

Fibrinogen does not relate to cardiovascular or muscle manifestations in COPD: cross-sectional data from the ERICA study

Cardiovascular and skeletal muscle manifestations constitute important comorbidities in COPD, with systemic inflammation proposed as a common mechanistic link. Fibrinogen has prognostic role in COPD. We aimed to determine whether aortic stiffness and quadriceps weakness are linked in COPD, and whether they are associated with the systemic inflammatory mediator-fibrinogen. Aortic pulse wave velocity (aPWV), quadriceps maximal volitional contraction (QMVC) force and fibrinogen were measured in 729 patients with stable, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages II-IV COPD. The cardiovascular and muscular manifestations exist independently (P=0.22, χ²). Fibrinogen was not associated with aPWV or QMVC (P=0.628 and P=0.621, respectively), making inflammation, as measured by plasma fibrinogen, an unlikely common aetiological factor.

Effects of the "Living well with COPD" intervention in primary care: a comparative study

The pivotal objective of chronic obstructive pulmonary disease (COPD) self-management programmes is behaviour change to avoid moderate and severe exacerbations and improve health related quality of life.In a prospectively planned, controlled study, COPD patients who participated in the "Living well with COPD" (LWWCOPD) self-management intervention were compared with usual care patients from the primary care COPD Cohort ICE COLD ERIC, who did not receive self-management intervention (NCT00706602) The primary outcome was behaviour change and disease-specific health related quality of life after 1 year. Secondary end-points included exacerbation rates. We calculated mixed linear, zero-inflated negative binomial and logistic regression models and used propensity scores to counteract confounding.467 patients, 71 from the LWWCOPD and 396 from the usual care cohort, were included. The differences between intervention and control were 0.54 (95% CI 0.13-0.94) on the Chronic Respiratory Questionnaire domain "mastery", 0.55 (95% CI 0.11-0.99) on "fatigue", 0.54 (0.14-0.93) on "emotional function" and 0.64 (95% CI 0.14-1.14) on "dyspnoea". The intervention considerably reduced the risk of moderate and severe exacerbations (incidence rate ratio 0.36, 95% CI 0.25-0.52).Self-management coaching in primary care improves health-related quality of life and lowers exacerbation rates and health care use.

Physical activity in patients with COPD: the impact of comorbidities

INTRODUCTION

Comorbidities are common in patients with chronic obstructive pulmonary disease (COPD) and it plays an important role on physical activity (PA) in this population. Since low PA levels have been described as a key factor to predict morbi-mortality in COPD, it seems crucial to review the current literature available on this topic. Areas covered: This review covers the most common comorbidities found in COPD, their prevalence and prognostic implications. We explore the differences in PA between COPD patients with and without comorbidities, as well as the impact of the number or type of comorbidities on activity levels of this population. The effect of different comorbidities on activities of daily living in patients with COPD is also reviewed. Finally, we discuss options for the treatment of inactivity in COPD patients considering their comorbidities and limitations. Expert commentary: Comorbidities are highly prevalent in patients with COPD and further deteriorate PA levels in this population. Despite the wide range of interventions available in COPD, the evidence in the field seems to point at PA coaching with feedback on individual goals and longer lasting PR programmes with more than 12 weeks of duration when attempting to raise the activity levels of this population.

Prediction of long-term clinical outcomes using simple functional exercise performance tests in patients with COPD: a 5-year prospective cohort study

The 1-min sit-to-stand (1-min STS) test and handgrip strength test have been proposed as simple tests of functional exercise performance in chronic obstructive pulmonary disease (COPD) patients. We assessed the long-term (5-year) predictive performance of the 1-min sit-to-stand and handgrip strength tests for mortality, health-related quality of life (HRQoL) and exacerbations in COPD patients. In 409 primary care patients, we found the 1-min STS test to be strongly associated with long-term morality (hazard ratio per 3 more repetitions: 0.81, 95% CI 0.65 to 0.86) and moderately associated with long-term HRQoL. Neither test was associated with exacerbations. Our results suggest that the 1-min STS test may be useful for assessing the health status and long-term prognosis of COPD patients. This study was registered at http://www.clinicaltrials.gov/ (NCT00706602, 25 June 2008).

Physical activity and risk of comorbidities in patients with chronic obstructive pulmonary disease: a cohort study

Multi-morbidity is common in patients with chronic obstructive pulmonary disease and low levels of physical activity are hypothesized to be an important risk factor. The current study aimed to assess the longitudinal association between physical activity and risk of seven categories of comorbidity in chronic obstructive pulmonary disease patients. The study included 409 patients from primary care practice in the Netherlands and Switzerland. We assessed physical activity using the Longitudinal Ageing Study Amsterdam Physical Activity Questionnaire at baseline and followed patients for up to 5 years. During follow-up, patients reported their comorbidities (cardiovascular, neurological, endocrine, musculoskeletal, malignant, and infectious diseases) and completed the Hospital Anxiety and Depression Scale questionnaire for mental health assessment. We implemented multinomial logistic regression (an approximation to discrete time survival model using death as a competing risk) for our analysis. Study results did not suggest a statistically significant association of baseline physical activity with the development of seven categories of comorbidity. However, when we focused on depression and anxiety symptoms, we found that higher levels of physical activity at baseline were associated with a lower risk for depression (adjusted hazard ratio, 0.85; 0.75–0.95; p = 0.005) and anxiety (adjusted hazard ratio, 0.89; 0.79–1.00; p = 0.045). In chronic obstructive pulmonary disease patients, those with high physical activity are less likely to develop depression or anxiety symptoms over time. Increasing physical activity in chronic obstructive pulmonary disease patients may be an approach for testing to lower the burden from incident depression and anxiety.

Patients with chronic lung disease who stay physically active could reduce their chances of depression and anxiety. Milo Puhan at the University of Zurich, Switzerland, and co-workers assessed the association between physical activity and the risk of developing various co-existing diseases in 409 patients with chronic obstructive pulmonary disease (COPD). Co-morbidities such as cardiovascular diseases, diabetes and depression are prevalent in patients with COPD, but the reasons why are not clear. Puhan’s team assessed patients’ activity levels using an existing questionnaire, and administered another questionnaire to assess mental health. They followed the cohort for 5 years. Results indicated weak associations between physical activity levels and most physical illnesses, but there were significant links between higher levels of physical activity and a reduced risk of depression and anxiety. The results could inform novel COPD treatment programs.

Bias away from the null due to miscounted outcomes? A case study on the TORCH trial

Count outcomes occur in virtually all disciplines, such as medicine, epidemiology or biology, but they often contain error. Recently, it has been shown that self-reported numbers of exacerbations of Chronic Obstructive Pulmonary Disease patients can be considerably miscounted. Motivated by this result, we reanalysed data from the Towards a Revolution in Chronic Obstructive Pulmonary Disease Health trial, a large randomized controlled trial with the self-reported number of exacerbations of Chronic Obstructive Pulmonary Disease patients as outcome. To adjust for miscounting error in the response of Poisson and (zero-inflated) negative binomial models, we introduce novel, general methodology. The key idea is to formulate a zero-inflated negative binomial model to capture the error mechanism. This parametric approach automatically circumvents drawbacks of previously suggested methodology that treats miscounted outcomes in the misclassification framework. Prior information for the response error model parameters was elicited from validation data of an external study and adaptively weighted to account for potential prior-data conflict. The results of the Bayesian hierarchical modelling approach indicated that the treatment effect has been overestimated in the original study. However, closer inspection revealed that this unexpected result was an artefact of an unaccounted time dependency of the treatment effect.

The Inaccuracy of Patient Recall for COPD Exacerbation Rate Estimation and Its Implications: Results from Central Adjudication

BACKGROUND

COPD exacerbation incidence rates are often ascertained retrospectively through patient recall and self-reports. We compared exacerbation ascertainment through patient self-reports and single-physician chart review to central adjudication by a committee and explored determinants and consequences of misclassification.

METHODS

Self-reported exacerbations (event-based definition) in 409 primary care patients with COPD participating in the International Collaborative Effort on Chronic Obstructive Lung Disease: Exacerbation Risk Index Cohorts (ICE COLD ERIC) cohort were ascertained every 6 months over 3 years. Exacerbations were adjudicated by single experienced physicians and an adjudication committee who had information from patient charts. We assessed the accuracy (sensitivities and specificities) of self-reports and single-physician chart review against a central adjudication committee (AC) (reference standard). We used multinomial logistic regression and bootstrap stability analyses to explore determinants of misclassifications.

RESULTS

The AC identified 648 exacerbations, corresponding to an incidence rate of 0.60 ± 0.83 exacerbations/patient-year and a cumulative incidence proportion of 58.9%. Patients self-reported 841 exacerbations (incidence rate, 0.75 ± 1.01; incidence proportion, 59.7%). The sensitivity and specificity of self-reports were 84% and 76%, respectively, those of single-physician chart review were between 89% and 96% and 87% and 99%, respectively. The multinomial regression model and bootstrap selection showed that having experienced more exacerbations was the only factor consistently associated with underreporting and overreporting of exacerbations (underreporters: relative risk ratio [RRR], 2.16; 95% CI, 1.76-2.65 and overreporters: RRR, 1.67; 95% CI, 1.39-2.00).

CONCLUSIONS

Patient 6-month recall of exacerbation events are inaccurate. This may lead to inaccurate estimates of incidence measures and underestimation of treatment effects. The use of multiple data sources combined with event adjudication could substantially reduce sample size requirements and possibly cost of studies.

CLINICAL TRIAL REGISTRATION

www.ClinicalTrials.gov, NCT00706602.

Determinants of Physical Activity in Patients with Chronic Obstructive Pulmonary Disease: A 5-Year Prospective Follow-Up Study

BACKGROUND

Although many studies examined determinants of physical activity in patients with chronic obstructive pulmonary disease (COPD), most were cross-sectional and focused on single determinants only.

OBJECTIVES

The aim of this study was to determine how COPD patients' physical activity changes over time and to identify the determinants of physical activity using multivariable and longitudinal methods.

METHODS

In a prospective cohort study, 409 primary care patients with COPD in the Netherlands and Switzerland were followed for up to 5 years. Physical activity was assessed at baseline and every 6 months using the Longitudinal Aging Study Amsterdam Physical Activity Questionnaire (LAPAQ) adapted to a 0- to 23-point scale. We studied the associations between determinants at baseline and patients' long-term physical activity levels using linear mixed models.

RESULTS

Unadjusted analysis showed an overall gradual decline in physical activity (0.22 points of the LAPAQ scale every 6 months, 95% CI: 0.17-0.28; p < 0.001). In multivariable analyses, baseline determinants that were independently associated (p ≤ 0.05) with lower long-term physical activity levels included (starting from coefficients with the smallest p value) lower exercise capacity, older age, working, more smoking pack-years, more fatigued, male sex, lower educational levels, previously not in fitness programs, more depressed, lower lung function, lower overall health status, and more prescription drug use.

CONCLUSIONS

We found that physical activity of COPD patients may decline more than reported in the healthy elderly. Longitudinal analysis identified independent determinants of physical activity, which allows the identification of patients having low physical activity levels and who may benefit from physical activity interventions.

COPD biomarkers as tools for decision making in early clinical drug development

In this perspective article, we discuss, from a statistician's perspective, how biomarkers can be useful in decision making in drug development with emphasis on early clinical development (Phase I and II) in chronic obstructive pulmonary disease. We illustrate with examples of how biomarkers can affect the very choice of treatment strategy: for example, targeting patients in early versus late phases of the disease or patients with particular extrapulmonary manifestations of chronic obstructive pulmonary disease. We also illustrate the use of biomarkers for establishing proof of mechanism in Phase I trials and how surrogate biomarkers can be used as end points in Phase II leading to shorter and more efficient proof-of-principle and dose-finding trials.

Validation of prediction models based on lasso regression with multiply imputed data

Background

In prognostic studies, the lasso technique is attractive since it improves the quality of predictions by shrinking regression coefficients, compared to predictions based on a model fitted via unpenalized maximum likelihood. Since some coefficients are set to zero, parsimony is achieved as well. It is unclear whether the performance of a model fitted using the lasso still shows some optimism. Bootstrap methods have been advocated to quantify optimism and generalize model performance to new subjects. It is unclear how resampling should be performed in the presence of multiply imputed data.

Method

The data were based on a cohort of Chronic Obstructive Pulmonary Disease patients. We constructed models to predict Chronic Respiratory Questionnaire dyspnea 6 months ahead. Optimism of the lasso model was investigated by comparing 4 approaches of handling multiply imputed data in the bootstrap procedure, using the study data and simulated data sets. In the first 3 approaches, data sets that had been completed via multiple imputation (MI) were resampled, while the fourth approach resampled the incomplete data set and then performed MI.

Results

The discriminative model performance of the lasso was optimistic. There was suboptimal calibration due to over-shrinkage. The estimate of optimism was sensitive to the choice of handling imputed data in the bootstrap resampling procedure. Resampling the completed data sets underestimates optimism, especially if, within a bootstrap step, selected individuals differ over the imputed data sets. Incorporating the MI procedure in the validation yields estimates of optimism that are closer to the true value, albeit slightly too larger.

Conclusion

Performance of prognostic models constructed using the lasso technique can be optimistic as well. Results of the internal validation are sensitive to how bootstrap resampling is performed.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2288-14-116) contains supplementary material, which is available to authorized users.

Prediction of COPD-specific health-related quality of life in primary care COPD patients: a prospective cohort study

Background:

Health-related quality of life (HRQL) is an important patient-reported outcome for chronic obstructive pulmonary disease (COPD).

Aim:

We developed models predicting chronic respiratory questionnaire (CRQ) dyspnoea, fatigue, emotional function, mastery and overall HRQL at 6 and 24 months using predictors easily available in primary care.

Methods:

We used the “least absolute shrinkage and selection operator” (lasso) method to build the models and assessed their predictive performance. Results were displayed using nomograms.

Results:

For each domain-specific CRQ outcome, the corresponding score at baseline was the best predictor. Depending on the domain, these predictions could be improved by adding one to six other predictors, such as the other domain-specific CRQ scores, health status and depression score. To predict overall HRQL, fatigue and dyspnoea scores were the best predictors. Predicted and observed values were on average the same, indicating good calibration. Explained variance ranged from 0.23 to 0.58, indicating good discrimination.

Conclusions:

To predict COPD-specific HRQL in primary care COPD patients, previous HRQL was the best predictor in our models. Asking patients explicitly about dyspnoea, fatigue, depression and how they cope with COPD provides additional important information about future HRQL whereas FEV₁ or other commonly used predictors add little to the prediction of HRQL.

The ADO index as a predictor of two-year mortality in general practice-based chronic obstructive pulmonary disease cohorts

BACKGROUND

Existing prediction models for mortality in chronic obstructive pulmonary disease (COPD) patients have not yet been validated in primary care, which is where the majority of patients receive care.

OBJECTIVES

Our aim was to validate the ADO (age, dyspnoea, airflow obstruction) index as a predictor of 2-year mortality in 2 general practice-based COPD cohorts.

METHODS

Six hundred and forty-six patients with COPD with GOLD (Global Initiative for Chronic Obstructive Lung Disease) stages I-IV were enrolled by their general practitioners and followed for 2 years. The ADO regression equation was used to predict a 2-year risk of all-cause mortality in each patient and this risk was compared with the observed 2-year mortality. Discrimination and calibration were assessed as well as the strength of association between the 15-point ADO score and the observed 2-year all-cause mortality.

RESULTS

Fifty-two (8.1%) patients died during the 2-year follow-up period. Discrimination with the ADO index was excellent with an area under the curve of 0.78 [95% confidence interval (CI) 0.71-0.84]. Overall, the predicted and observed risks matched well and visual inspection revealed no important differences between them across 10 risk classes (p = 0.68). The odds ratio for death per point increase according to the ADO index was 1.50 (95% CI 1.31-1.71).

CONCLUSIONS

The ADO index showed excellent prediction properties in an out-of-population validation carried out in COPD patients from primary care settings.

Five comorbidities reflected the health status in patients with chronic obstructive pulmonary disease: the newly developed COMCOLD index

OBJECTIVE

This study aimed to identify those comorbidities with greatest impact on patient-reported health status in patients with chronic obstructive pulmonary disease (COPD) and to develop a comorbidity index that reflects their combined impact.

STUDY DESIGN AND SETTING

We included 408 Swiss and Dutch primary care patients with COPD from the International Collaborative Effort on Chronic Obstructive Lung Disease: Exacerbation Risk Index Cohorts (ICE COLD ERIC) in this cross-sectional analysis. Primary outcome was the Feeling Thermometer, a patient-reported health status instrument. We assessed the impact of comorbidities at five cohort assessment times using multiple linear regression adjusted for FEV1, retaining comorbidities with associations P ≤ 0.1. We developed an index that reflects strength of association of comorbidities with health status.

RESULTS

Depression (prevalence: 13.0%; regression coefficient: -9.00; 95% CI: -13.52, -4.48), anxiety (prevalence: 11.8%; regression coefficient: -5.53; 95% CI -10.25, -0.81), peripheral artery disease (prevalence: 6.4%; regression coefficient: -5.02; 95% CI-10.64, 0.60), cerebrovascular disease (prevalence: 8.8%; regression coefficient: -4.57; 95% CI -9.43, 0.29), and symptomatic heart disease (prevalence: 20.3%; regression coefficient: -3.81; 95% CI -7.23, -0.39) were most strongly associated with the Feeling Thermometer. These five comorbidities, weighted, compose the COMorbidities in Chronic Obstructive Lung Disease (COMCOLD) index.

CONCLUSION

The COMCOLD index reflects the combined impact of five important comorbidities from patients' perspective and complements existing comorbidity indices that predict death. It may help clinicians focus on comorbidities affecting patients' health status the most.

Musculoskeletal disorders in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by airway obstruction and inflammation but also accompanied by several extrapulmonary consequences, such as skeletal muscle weakness and osteoporosis. Skeletal muscle weakness is of major concern, since it leads to poor functional capacity, impaired health status, increased healthcare utilization, and even mortality, independently of lung function. Osteoporosis leads to fractures and is associated with increased mortality, functional decline, loss of quality of life, and need for institutionalization. Therefore, the presence of the combination of these comorbidities will have a negative impact on daily life in patients with COPD. In this review, we will focus on these two comorbidities, their prevalence in COPD, combined risk factors, and pathogenesis. We will try to prove the clustering of these comorbidities and discuss possible preventive or therapeutic strategies.

Risk factors and comorbidities in the preclinical stages of chronic obstructive pulmonary disease

RATIONALE

There is little information about comorbidities and their risk factors in the preclinical stages of chronic obstructive pulmonary disease (COPD).

OBJECTIVES

This study aims to investigate the prevalence of premorbid risk factors and comorbid diseases and its association with daily physical activity in subjects detected with COPD by spirometry screening.

METHODS

Sixty subjects with preclinical COPD (63 ± 6 yr; 68% [n = 41] male) were compared with 60 smoking control subjects (62 ± 7 yr; 70% [n = 42] male) and 60 never-smoking control subjects (62 ± 6 yr; 57% [n = 34] male). Comorbidities (cardiovascular, metabolic, and musculoskeletal disease) and daily physical activity (by multisensor activity monitor) were measured objectively.

MEASUREMENTS AND MAIN RESULTS

The prevalence of premorbid risk factors and comorbid diseases was significantly higher in preclinical COPD compared with age-matched never-smoking control subjects, but was similar to smoking control subjects not suffering from COPD. In preclinical COPD and smoking control subjects, the combination of cardiovascular disease and musculoskeletal disease was the most prevalent (15% [n = 9] and 12% [n = 7], respectively). In a multivariate logistic regression analysis, physical inactivity and smoking were found to be independent risk factors for having greater than or equal to two comorbidities.

CONCLUSIONS

Premorbid risk factors and comorbid diseases were more prevalent in the preclinical stages of COPD and smokers without COPD. Physical inactivity and smoking were more strongly associated with the presence of comorbidities compared with airflow obstruction. Clinical trial registered with www.clinicaltrials.gov (NCT 01314807).

Clusters of comorbidities based on validated objective measurements and systemic inflammation in patients with chronic obstructive pulmonary disease

RATIONALE

Comorbidities contribute to disease severity and mortality in patients with chronic obstructive pulmonary disease (COPD). Comorbidities have been studied individually and were mostly based on self-reports. The coexistence of objectively identified comorbidities and the role of low-grade systemic inflammation in the pathophysiology of COPD remain to be elucidated.

OBJECTIVES

To cluster 13 clinically important objectively identified comorbidities, and to characterize the comorbidity clusters in terms of clinical outcomes and systemic inflammation.

METHODS

A total of 213 patients with COPD (FEV1, 51 ± 17% predicted; men, 59%; age, 64 ± 7 yr) were included prospectively. Comorbidities were based on well-known cut-offs identified in the peer-reviewed English literature. Systemic inflammatory biomarkers were determined in all patients. Self-organizing maps were used to generate comorbidity clusters.

MEASUREMENTS AND MAIN RESULTS

A total of 97.7% of all patients had one or more comorbidities and 53.5% had four or more comorbidities. Five comorbidity clusters were identified: (1) less comorbidity, (2) cardiovascular, (3) cachectic, (4) metabolic, and (5) psychological. Comorbidity clusters differed in health status but were comparable with respect to disease severity. An increased inflammatory state was observed only for tumor necrosis factor (TNF) receptors in the metabolic cluster (geometric mean [lower and upper limit]; TNF-R1, 2,377 [1,850, 3,055] pg/ml, confidence, 98.5%; TNF-R2, 4,080 [3,115, 5,344] pg/ml, confidence, 98.8%) and only for IL-6 in the cardiovascular cluster (IL-6, 3.4 [1.8, 6.6] pg/ml; confidence, 99.8%).

CONCLUSIONS

Multimorbidity is common in patients with COPD, and different comorbidity clusters can be identified. Low-grade systemic inflammation is mostly comparable among comorbidity clusters. Increasing knowledge on the interactions between comorbidities increases the understanding of their development and contributes to strategies for prevention or improved treatment.

Simple functional performance tests and mortality in COPD

Exercise tests are important to characterise chronic obstructive pulmonary disease patients and predict their prognosis, but are often not available outside of rehabilitation or research settings. Our aim was to assess the predictive performance of the sit-to-stand and handgrip strength tests.

The prospective cohort study in Dutch and Swiss primary care settings included a broad spectrum of patients (n=409) with Global Initiative for Chronic Obstructive Lung Disease stages II to IV. To assess the association of the tests with outcomes, we used Cox proportional hazards (mortality), negative binomial (centrally adjudicated exacerbations) and mixed linear regression models (longitudinal health-related quality of life) while adjusting for age, sex and severity of disease.

The sit-to-stand test was strongly (adjusted hazard ratio per five more repetitions of 0.58, 95% CI 0.40–0.85; p=0.004) and the handgrip strength test moderately strongly (0.84, 95% CI 0.72–1.00; p=0.04) associated with mortality. Both tests were also significantly associated with health-related quality of life but not with exacerbations. The sit-to-stand test alone was a stronger predictor of 2-year mortality (area under curve 0.78) than body mass index (0.52), forced expiratory volume in 1 s (0.61), dyspnoea (0.63) and handgrip strength (0.62).

The sit-to-stand test may close an important gap in the evaluation of exercise capacity and prognosis of chronic obstructive pulmonary disease patients across practice settings.

The 1-min sit-to-stand test predicts mortality in COPD patients and can easily be implemented across practice settingshttp://ow.ly/mxrPx